NASA received a critical signal from one of its most distant spacecrafts this morning, confirming that the vehicle has just flown by a tiny frozen rock in the outer reaches of the Solar System. From a report: That space probe, named New Horizons, has now made history. Currently located more than 4 billion miles from Earth, the spacecraft has now whizzed past the most distant -- and most primitive -- object that's ever been visited by humanity. 'We have a healthy spacecraft,' Alice Bowman, the mission operations manager for the New Horizons mission, said after confirming the feat. 'We've just accomplished the most distant flyby.'

'It's a flyby that's been over a decade in the making, too. Launched in 2006, New Horizons famously passed by Pluto in 2015, becoming the first mission to ever reach the dwarf planet. But ever since that flyby, New Horizons has kept on speeding through the Solar System, in order to meet up with this new object, nicknamed Ultima Thule.